Fluidic respirator



Feb. 10,' 1970 COMPRESSOR E. N. KIMBALL FLUIDIC RESPIRATOR Filed Feb. 5, 1968 INVENTOR. Eon 0v /V. K/MBALL United States Patent 3,494,357 FLUIDIC RESPIRATOR Edwin N. Kimball, Salt Lake City, Utah, assignor to Sperry Rand Corporation, a corporation of Delaware Filed Feb. 5, 1968, Ser. No. 702,961 Int. Cl. A61h 31/00; A62b 7/00; F15c 1/08 US. Cl. 128145.6 6 Claims ABSTRACT OF THE DISCLOSURE A respirator for assisting in breathing which utilizes fluidic components for providing an inexpensive, reliable and relatively simple apparatus.

The respirator comprises two fluidic control means connected to a pressurized gas source, sensitivity adjusting means regulating said fluidic controls with a fluidic diode for insuring one directional flow, positioned between said control means and delivery mask.

BACKGROUND OF THE INVENTION Field of the invention The present invention pertains to fluidic respirators for assisting the breathing functions of human beings.

Description of the prior art Prior art types of respirators or resuscitators generally include elements having moving parts wherein their relative juxtaposition results in a delicate apparatus which under the continuous, repetitive cycle of the breathing function tends to wear and change its sensitivity. This results in a relatively expensive and complex device which is difficult to maintain in continuous operation and also results in changes in its operation over long periods of time. Further, the expense and complexity of the prior art devices normally precludes their use in the home and for widespread military application except in special circumstances. In certain instances, particularly when used for emergency situations, prior art devices may be called upon to operate after long periods of storage and the delicate moving parts may have deteriorated to the point of malfunction.

SUMMARY OF THE INVENTION The present invention utilizes a unique combination of fluidic logic units to maintain inhalation and exhalation at a controlled rate without requiring any moving elements. The fluidic respirator of the present invention therefore provides an extremely simple and reliable device which operates accurately over long periods of continuous use and can be stored indefinitely without damage or deterioration of its components.

BRIEF DESCRIPTION OF THE DRAWING The single figure of the drawing shows a schematic diagram of a fluidic respirator in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, a source of air under pressure which may be provided, for example, by a compressor 10 provides air at pounds per square inch to the power stream port 11 of a fluidic bistable power amplifier 12. Compressed air at 2 pounds per square inch is also provided from the compressor via a regulator 13 to an adjustable breathing rate valve 14 and to the input power stream ports 15, 16 and 17 of NOR gates 18, 19 and 20, respectively. A fluidic resistor 24 is disposed in a bypass 25 around the rate valve 14 to establish a mini- 3,494,357 Ice Patented Feb. 10, 1970 mum sensitivity for the fluidic respirator system 26, in a manner to be more fully explained.

One control stream port 27 of the NOR gate 18 is connected to the junction of the rate valve 14 and the resistor 24. The other control stream port 28 of the NOR gate 18 is connected via conduit 29 to a patient mask 30. One output conduit 31 of the NOR gate 18 is vented to atmosphere while its other output conduit 32 is connected to a control stream port 33 of the NOR gate 19. One output conduit 34 of the NOR gate 19 is vented to atmosphere while its other output conduit 35 is connected to an output conduit port 36 which in turn couples to a control stream port 37 of the bistable power amplifier 12. The output conduit 35 is also connected through an output port 38 to a control stream port 40 of the NOR gate 20. The other control stream port 41 of the NOR gate 20 is responsive to the exhalation of the patient via the mask 30, the conduit 29, an adjustable pressure regulating valve 42 and a fluid resistor 43.

One output conduit 44 of the Nor gate 20 is vented to atmosphere while its other output conduit 45 is connected via an output port 46 to the control stream port 47 of the NOR gate 19. The output conduit 45 is also connected via an output port 48 to the control stream port 49 of the bistable power amplifier 12. The NOR gates 19 and 20 interconnected as described, provide a driver bistable 50. One output conduit 51 of the bistable power amplifier 12 is vented to atmosphere while its other output conduit 52 is connected through a fluidic diode 53 to the patient mask 30. The diode 53 is vented in the backward flow direction to exhaust a portion of the exhaled air. A patient pressure meter 54 is connected via conduit 29 to the patient mask 30 to provide an indication of the pressure in the patients lungs.

In operation, when the patient starts to inhale through the patient mask 30, a negative pressure develops in the conduit 29. This negative pressure is transmitted via conduit 29 to the control stream port 28 and causes the NOR gate 18 to switch its power stream from its vented output conduit 31 to the output conduit 32. The power stream output from the output conduit 32 of the NOR gate 18 is applied to the control stream port 33 to produce a control stream in the NOR gate 19 that diverts the power stream of the NOR gate 19, which normally flows through the output conduit 35, to the vented output conduit 34. This switches the driver bistable 50 to a reset condition and removes the control stream applied via port 37 in the bistable power amplifier 12. The absence of fluid fiow through the output conduit 35, the output port 38, and the input port 40 eliminates the control stream in the NOR gate 20 since the patient is inhaling and there is no positive pressure applied to the input port 41 via conduit 29. The power stream of the NOR gate 20 thus flows through the output conduit 45 and the output port 48 to be applied as a control stream in the bistable amplifier 12 via control stream port 49. The power stream of the NOR gate 20 also flows through the output port 46 and the input port 47 to continue to divert the power stream of the NOR gate 19 to flow through the vented output conduit 34. The power stream of the bistable amplifier 12 is switched from its vented output conduit 51 to the output conduit 52.

The flow from the output conduit 52 is passed through the fluid diode 53 and into the patient mask 30 which causes the air to build up in the patients lungs. As the volume of the moving air builds up in the patients lungs, the pressure increases in the conduit 29 until the power stream of the NOR gate 18 is diverted to its vented output conduit 31 by the control stream entering via input port 28. The pressure is indicated on the patient pressure meter 54. The pressure continues to increase until, as

letermined by the setting of the pressure valve 42, there 5 sufficient fiow through the pressure valve 42 to again et the driver bistable 50 via resistor 43. When there is ufiicient pressure to set the driver bistable 50, the conrol stream of the NOR gate via input port 41 causes he power stream of the NOR gate 20 to be diverted to its ented output conduit 44 from the output conduit 45. ["he absence of fluid flow through the output conduit 45 1nd output port 46 removes the control stream of the 510R gate 19 entering via input port 47. Since there is no low through the input port 33, the power stream of the IOR gate 19 is now permitted to flow through output :onduit 35, output port 36 and input port 37 where it acts is a control stream to divert the power stream of the :istable amplifier 12 to its vented output conduit 51. There is no control stream entering via input port 49 since here is no flow through the output conduit 45 at this Lime. The patient is now permitted to exhale through the ents on the backwardly vented diode 53. When the pa- ;ient starts to inhale, the cycle is repeated as indicated above.

The rate valve 14 is used to control the sensitivity of the NOR gate 18. As the rate valve 14 is opened, a bias is applied via the control stream input port 27 and sensitivity increases. With increased sensitivity, a point is reached where the fluidic respirator system 26 does not need a negative pressure in the patient mask 30 to switch the NOR gate 18. The respirator system 26 will then automatically start the breathing cycle for the patient. As the valve 14 is opened further, the bias is increased and the breathing rate is increased. In this mode of operation, the rate is determined by the volume of the patients lungs, the pressure to which they are to be filled, and the rate of patients exhalation. The fluidic resistor 24 is utilized to establish a minimum sensitivity in the respirator system 26. This is accomplished by bypassing the rate valve 14 with a metered amount of air. The purpose of the fluidic resistor 43 is to render the sensitivity of the pressure valve 42 more uniform by slowing the flow of air from the valve 42.

While the invention has been described in its preferred embodiment, it is to be understood that the words which have been used are words of description rather than limitation and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention in its broader aspects.

I claim:

1. Fluidic respirator apparatus comprising a source of gas under pressure,

first fluidic control means having a power stream connected to said gas source, first and second control streams, and first and second output conduits,

sensitivity adjusting means connected between said gas source and said first control stream for adjusting the sensitivity of said first fluidic control means for controlling the rate of breathing,

second fluidic control means having a power stream connected to said gas. source, first and second control streams, and first and second output conduits, said first output conduits being vented to atmosphere, fluidic driver means connected between said first and second control means and responsive to the output of said second output conduit of said first control means for controlling said second control means, respirator mask means,

fluidic diode means connected between said second output conduit of said second control means and said mask means for providing unidirectional flow to said mask means,

and conduit means connected between said mask means and said second control stream of said first control means.

2. Apparatus of the character recited in claim 1 including pressure regulating means connected between said conduit means and said driver means for regulating the breathing pressure.

3. Apparatus of the character recited in claim 1 in which said fluidic driver means includes interconnected first and second fluidic NOR gate means each having a power stream connected to said gas source, first and second control streams, and first and second output conduits, with said first output conduits being vented to atmosphere and each of said second output conduits being cross connected to respective second control streams of the other NOR gate means to provide set and reset functions.

4. Apparatus of the character recited in claim 3 and further including pressure regulating means connected between said conduit means and said second control stream of said second NOR gate means for regulating the maximum breathing pressure by setting said driver means.

5. Apparatus of the character recited in claim 4 in which said pressure regulating means includes a pressure regulating valve in series with a fluidic resistor for slowing the flow of said gas from said pressure regulating valve.

6. Apparatus of the character recited in claim 1 in which said sensitivity adjusting means includes a breathing rate valve having a bypass connection including a fluidic resistor for establishing a minimum sensitivity.

References Cited UNITED STATES PATENTS 3,191,611 6/1965 Bauer 137-8l.5 3,368,555 2/1968 'Beasley 128-145.8 3,435,822 4/1969 Ziermann et al. 128-145.6

RICHARD A. GAUDET, Primary Examiner G. F. DUNNE, Assistant Examiner US. Cl. X.R. 137-81.5 

